INGNITION KEY WILL NOT ROTATE TO START CA

After inserting the ingnition key, the key will not turn to start the car about 30% of the time. We have checked to ensure that the steering wheel is free and not " locked" and have checked the position of the gear shift to make sure it is in the " park position.

We live in Cabo San Lucas Mexico and the local Toyota dealer has looked at the car and stated that it looks fine. Because they have not experienced the key not working.